Five compounds (the CRH1 receptor antagonist SB723620, the NK1 antagonist G597599, the SSRI/5HT2A agonist Vilazodone, the antidepressant 8-hydroxy-bupropion, and the type 4 phosphodiesterase inhbitor SB207499), provided by GlaxoSmithKline as part of The Emory-GSK-NIMH Collaborative Mood Disorders Initiative, will be evaluated for anti-fear and anxiolytic activity using fear-potentiated, light-enhanced, and CRH-enhanced startle paradigms (increased startle in the presence of cues that predict shock, during sustained illumination, or following i.c.v. corticotropin-releasing hormone infusions, respectively). Whereas light- and CRH-enhanced startle (which are more akin to anxiety than to fear) are mediated by circuitry that includes the bed nucleus of the stria terminalis (BNST) but not the central nucleus of the amygdala (CeA), fear-potentiated startle is mediated by circuitry that includes the CeA but not the BNST. A central goal of the proposed studies will be to identify differing pharmacological vulnerabilities associated with BNST (anxiety) versus CeA (fear) dependent behaviors. In humans, anxiety disorders are more prevalent in women than in men and, in rats, light-enhanced startle is more robust in females than in males. Interestingly, the BNST is sexually dimorphic in both species. Thus, a second goal will be to compare the influence of gender on BNST- versus CeA-dependent responses, and to evaluate gender influences on drug responses in each model. These same compounds will be evaluated in other laboratories (separate applications) using different behavioral models and non-behavioral assays. It is hoped that this integrated effort will foster new approaches for the rapid evaluation of novel compounds with potential clinical utility.